Spray gun



Dec. 6, 1966 HUGHES 3,289,947

SPRAY GUN Filed Oct. 15, 1965 INVENTOR.

5421; K. HUGHES HTTOBNEY United States Patent 3,289,947 SPRAY GUN EarlK. Hughes, 1436 Olivina Ave., Livermore, Calif. Filed Oct. 15, 1965,Ser. No. 496,514 Claims. (Cl. 239-348) The present invention relates toimprovements in a spray gun and it consists in the combination,construction and arrangement of parts as hereinafter described andclaimed.

This spray gunis intended to be operated from an air compressor unit andnot from a storage tank of compressed air. In the usual non-bleeder typespray gun that is operated by a trigger, as soon as the operatorreleases the trigger so as to stop any further flow of compressed airthrough the gun, the air pressure will build up in the air hose and theair compressor will start to labor in its operation because it isforcing compressed air into a hose that is already filled with air.

An object of my invention is to provide a .spray gun that does not havea trigger operated valve. Instead the air passage in the spray gun has abranch exhaust passage with an open outlet end that vents to theatmosphere. The open outlet end is placed near to the hand-grip portionof the spray gun so that the operator can grip this portion with onehand when using the spray gun and can take the index finger of the samehand to close the outlet end of the branch exhaust passage. His fingertakes the place of the trigger operated valve of the usual spray gun andwhen it closes the outer end of the branch exhaust passage, thecompressed air will flow through the gun to operate a novel sprayingmechanism. When the operator wants to stop the spraying mechanism fromoperating while the air compressor is still working, he

merely removes his finger from the outlet end of the branch exhaustpassage. All of the compressed air from the air compressor will now beby-passed to the branch exhaust passage and be expelled to theatmosphere. The air compressor will not labor because there will be nobuilding up of air back pressure. This may be termed a free bleeding ofthe air when the gun is not being used and is still connected to the aircompressor. The spray gun will also be less expensive to manufacturebecause no trigger actuated valve is needed.

A further object of my invention is to provide a spray gun in which thenovel spraying mechanism can be adjusted to spray a mist of liquid suchas a stain or paint and also to spray droplets of the liquid. In many ofthe familiar types of spray guns there is an air delivery tube formoving a stream of air over the top of a liquid delivery tube whoselower end is immersed in the liquid to be sprayed. An entraining actionof the liquid in the liquid conveying tube results and the liquid in thecontainer will be drawn up in the liquid-conveying tube and will beatomized by the air stream.

In my novel spraying mechanism the horizontal tub is carefullypositioned, far enough from the vertical tube, so that no entrainingaction of the liquid takes place. Instead, the mechanism delivers airinto the top of the liquid container creating a mild air pressure ofsuflicient force to cause the liquid in the container to be forced intothe vertical tube and to rise to the top of the tube. A horizontalstream of air is directed against the liquid at the point where itreaches the top of the vertical tube; the air is of suflicient force toatomize the liquid. As will be explained more fully hereinafter, theamount of air entering the container top can be controlled andconsequently the rate of flow of liquid is also controllable. Thequantity of air flowing horizontally over the top of the liquidconveying tube can also be controlled for either atomizing the liquid orbreaking it up into droplets of varying sizes as desired.

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Simplicity of structure is a main factor in this invention. The aircompressor will operate cooler and with less strain because there is nobuild up of back pressure When actual spraying stops. There is nomechanism to clean and oil which is required when a trigger operatedvalve is used. By making simple adjustments the operator can produce alight or heavy spray or a spatter.

Other objects and advantages will appear as the specification continues.The novel features of the invention will be set forth in the appendedclaims.

Drawing For a better understanding of my invention, reference should bemade to the accompanying drawing, forming part of this specification, inwhich:

FIG. 1 is a side elevation of the spray gun with parts being shown insection.

FIGURE 2 is a top plan view of FIGURE 1.

FIGURE 3 is a side elevation of a portion of the spray gun and theliquid holding container. 1

FIGURE 4 is a transverse section taken along the line 4-4 of FIGURE 1.

While I have shown only the preferred form of my invention, it should beunderstood that various changes, or

modifications, may be made within the scope of the annexed claimswithout departing from the spirit thereof.

Detailed description In carrying out my invention, I provide a spray gunthat has a body with ahandle grip portion A and a channel-shaped memberB. The handle may be made of wood or plastic while the channel-shapedmember B is made of metal. It is possible to have the handle gripportion and the channel-shaped member cast as a single piece from aplastic or metal so I do not wish to be confined to the particulardesign and arrangement of these two parts.

The handle grip portion A has a top edge 10 and the sides of the memberA that are disposed adjacentto the top 10 are provided with grooves 11for receiving the side flanges 12 of the channel-shaped member B. Screws13 and 14 or other suitable fastening means, see FIGURE 1, may be usedfor securing the channel-shaped member to the top of the handle gripportion A.

In FIGURE 2, I show the top of the channel-shaped member B and its willbe noted that it has a disc-shaped end B. This disc-shaped end has acontainer cap C secured thereto by rivets 15, see FIGURE 1. The cap Chas an annular flange 16 that is threaded for receiving the threadedneck 17 of a fluid container indicated generally at D. The fluidcontainer may be of any size desired.

The handle grip portion A has an air passage 18 that is in communicationwith an air hose E. The air hose in turn is connected to an aircompressor, not shown. My spray gun is not designed to be used with acornpressed air tank or reservoir. The air passage 18 has a branchpassage 18a communicating therewith and this leads to an air exhausttube F that projects from the edge 19 of the handle grip portion A.FIGURE 4 shows the air exhaust tube F provided with an exhaust opening20 in its side and this exhaust opening can be partly or completelyclosed by a sleeve valve G that is rotatably mounted on the air exhausttube F. The sleeve valve has an exhaust opening 21 that maybe broughtinto registration with the opening 20 of the air exhaust tube F asclearly shown in FIGURE 4. The handle grip portion A has a markerindicated by dotted lines 22 and this marker is placed adjacent to theperiphery 23 of the sleeve valve G. In addition the periphery or outercylindrical surface of the sleeve valve G is calibrated 3 with a numberof parallel markings indicated dotted lines 24 in FIGURE 1.

The operator can rotate the sleeve valve G on the air exhaust tube Finto a desired position for entirely closing the exhaust opening 20 orfor partially opening it or for entirely opening it as shown in FIGURE 4when the opening 21 in the sleeve valve is brought into registrationwith the opening 20. In addition the air exhaust tube F has an end 25that projects beyond the outer end 26 Oif the sleeve valve G and thisend opens to the atmosphere. The open end 25 of the air exhaust tube Fmay be closed by the finger of the operator in a manner hereinafterdescribed.

An air pipe H has its lower end communicating with the air passage 18and has its upper end closed as at 26'. The air pipe H projects throughan opening 27 in the channel-shaped member G. An air tube J communicateswith the air pipe H and parallels the top of the channel-shaped memberB. The air tube J extends through a bracket K that in turn is carried bythe channel-shaped member B. The outer end of the air tube J is in theshape of an air nozzle 28 and this air nozzle is positioned close to afluid outlet tube L. The tube L extends through aligned openings in thedisc-shaped end B and the cap C so as to be supported thereby. The tubeL extends into the liquid container D when the latter is secured to thecap C. A flexible tube L shown by the dotted lines in FIGURE 1, isconnected to the lower end of the fluid conveying tube L and may be longenough to accommodate liquid containers, not shown, that areconsiderably larger than the liquid container D illustrated in FIGURE 1.The bottom of the flexible tube L' has a nylon screen L2 attached toprevent any impurities from clogging the tube L.

I provide novel means for forcing air into the liquid container D sothat the air pressure built up within the container will force liquidout through the fluid outlet tube L. The purpose of the'nozzle 28 forthe air tube J is not for creating an entraining action which will drawfluid from the tube L but this nozzle will only project an air streamagainst the fluid that is forced out at the top of the fluid outlet pipeL. In the process of assembly, the end of the nozzle 28 is positioned toan exact spot Where the entraining action is eliminated. Such a spot isslightly to the rear of the tube L and just a trifle higher than theposition where the entraining action would be promoted. Novel means willpresently be described that controls the amount of air pressure createdin the top of the'liquid container D and this air pressure in turn willcontrol the amount of fluid discharged at the top of the tube L. In thisway the operator can control the quantity of fluid sprayed against asurface, not shown.

A second air tube M communicates with the air pipe H and is supported bythe bracket K. The air tube M parallels the first air tube J for anappreciable distance and then the air tube is inclined downwardly at anangle as clearly shown at M in FIGURE 1. The outer end of the second airtube M is provided with a nozzle 29 and FIGURE 3 illustrates this nozzleas pointing directly at an air inlet tube N that feeds air into the topof the container D. The upper end 30 of the air tube N is cut at anangle of substantially 45 and when the air inlet end 30 for the tube Nfaces the nozzle 29 as clearly shown in FIGURE 3, substantially all ofthe air issuing from the nozzle 29 will be received in the chamiered end30 of the tube N and will be directed into the top interior of thecontainer D. It is this air pressure in the top of the container thatwill force fluid P out through the flexible tube L and the fluid outlettube L and will deliver this fluid at the top end 31 of the fluid outlettube L.

I provide novel means for varying the quantity of air that enters theair inlet tube N. Both FIGURES 2 and 3 by the 4. show the air inlet tubeN rotatably mounted in the container cap C and the disc-shaped end B.The tube N is provided with a handle Q and this handle is disposed justabove the top of the disc-shaped end B. The handle Q is provided with apointer 32, see FIGURE 2, and this pointer travels over a series ofmarkings numbered 1 to 6 inclusive and indicated at R. The markings maybe depressions or projections in the disc-shaped end B or they may be ofa contrasting color to the main color of the disc-shaped end. Themarkings 1 through 6 are spaced equal distances apart and they form anarcuate row whose center is the rotating axis of the tube N.

When the pointer 32 for the handle or arm Q points toward the markingnumber 1, the chamfered entrance end of the air inlet tube N will befacing directly toward the nozzle 29 and will receive substantially allof the air issuing from the nozzle. As the handle Q is rotated in aclockwise direction in FIGURE 2, it will rotate the chainfered end 30gradually out of registration with the nozzle 29. As this rotationoccurs, less of the air issuing from the nozzle 29 will be received bythe inlet end 30 and therefore less air will be directed into the top ofthe liquid container D by means of the air inlet pipe N. The purpose ofthis will be explained more fully when describing the operation of thedevice.

When the pointer 32 ot the arm Q registers with a marking 7 which isjust to the right of the marking 6 in FIGURE 2, the plane of theinclined inlet end 30 for the tube N will be disposed in such a positionthat substantially no air will enter the opening 30. Therefore therewill be insuflicient air pressure in the top of the liquid container Dto force liquid P out through the fluid outlet tube L. The operator canin this manner control the amount of fluid issuing trom the top 31 ofthe tube. The lesser amount of fluid that is dispensed from the tube Lwill result in a less quantity of fluid being sprayed against a surface,not shown, by the air issuing from the nozzle 28 of the air tube J.

The sleeve 'valve G can be adjusted so as to entirely close the opening20 in the air exhaust tube F and therefore when the operator closes theoutlet end 25 of the tube F with his finger, all of the air entering thepassage 18 from the air compressor and the flexible hose E, will flowinto the tubes I and M with the result that the air from the tube M willbe used in forcing air into the top of the liquid container D andthereby forcing liquid out through the opening 31 of the tube L and theair issuing from the nozzle 28 of the tube I will be used for sprayingthe liquid issuing from the outlet end 31. This amount of air to bothtubes J and M can be reduced by rotating the sleeve valve G to partiallyuncover the opening 20 or to entirely uncover the opening 20 by bringingthe sleeve opening 21 into registration therewith. The operator keepshis index finger closing the open end 25 of the air exhaust tube Fduring all of this adjustment of parts and therefore more liquid will bedelivered from the, pipe L When the. opening 20 is closed by the sleevevalve G and more air will be forced from the nozzle 28 of the tube J tochange the liquid into a spray and cause it to be directed against asurface, not shown. The amount of liquid dispensed through the opening31 will be reduced as the opening 21 in the sleeve valve G is broughtmore and more into registration with the opening 20 in the exhaust tubeF. Also less air will be delivered through the nozzle 28 of the air tubeJ for changing the liquid issuing from the opening 31 of the tube Linto'a spray.

Operation The air hose E for the spray gun connects with an aircompressor, not shown, and when the operator wishes'to .cut oif thespraying of fluid against the surface of a short time, he merely freeshis index finger, not shown, to uncover the open end 25 of the airexhaust tube F. All'of the air flowing through the air hose E and intothe air passage 18 will flow out through the open end 25 of the airexhaust tube F into the atmosphere and there will be no back airpressure on the air compressor. Therefore the air compressor will notlabor unnecessarily while it is still delivering air to the spray gun ifthe operator is not momentarily spraying liquid from the container D.This is a novelconstruction and no trigger or valve mechanism is needed.All that is necessary to make the spray gun operable is for the operatorto use his forefinger to close the open end 25 of the air exhaust tubeF.

I have already explained how the amount of liquid delivered by the tubeL to the open end 31 of the tube can be altered by merely changing thequantity of air entering the top of the container through the air inletpipe M. This amount of air is changed by adjusting the sleeve valve G topermit a desired quantity of air to escape through the openings 20 and21 of the exhaust air tube F and the sleeve valve G respectively. Alsothe amount of air entering the top of the container can be additionallycontrolled by swinging the arm Q for rotating the tube N with respect tothe air nozzle 29 of the air tube M. When the pointer 32 is aligned withthe marking 7 on the top of the disc-shaped end B, practically no airwill be received by the tube N from the nozzle and no liquid will bedelivered to the open end 31 of the tube L. When the pointer 32 isaligned with the marking numbered 1, substantially all of the air fromthe nozzle 29 will enter the tube N and find its way into the top of thecontainer D. The greatest amount of liquid will therefore be deliveredfrom the opening 31 at the top of the tube L.

It is possible for the operator to spray a minimum amount of liquidagainst the surface and to thoroughly atomize this liquid. It is furtherpossible for the operator to deliver greater quantities of liquid and tocause it to be sprayed as droplets onto the surface rather than as amist. For example, when the air issuing from the nozzle 28 is at itsmaximum and the liquid issuing from the opening 21 at the tube L is atits minimum, the spray gun will deliver a fine mist of liquid againstthe surface. To obtain maximum amount of air for the nozzle 28, the openend 25 of the air exhaust F is closed by the operators index finger andthe sleeve valve G is closed. At the same time in order to obtain aminimum amount of liquid to issue from the opening 31 in the tube L, thehandle Q is swung for moving the pointer 32 so as to register with themarking 6 on the disc-shaped end B1. The maximum amount of air and alarger quantity of liquid can be realized when the handle Q swings thepointer 32 to the number 5 position in the row of markings R. The mistissuing from the opening 31 of the tube L can be made heavier byrotating the sleeve valve G.

As the pointer 32 is swung over the markings R, in a counter-clockwisedirection when looking at FIGURE 2, more air will enter the pipe N and agreater air pressure will be built up in the top of the liquid containerD and more liquid will be forced out from the opening 31 of the tube L.Thus various settings of the pointer 32 will cause the spray gun toproduce a mist or fogging up to a heavy spatter of liquid. The air fromthe nozzle 28 can also be varied. It might be implied from this that theair feed control for the nozzle 28 and the liquid feed control for theoutlet 31 of the tube L are independent of each other. Actually a changein the setting of the sleeve valve G will alter the air flow in both ofthe tubes J and M. Therefore from a more technical standpoint, theadjustment of the liquid flow at the top of the spray gun by means ofthe handle Q is a refinement in the proportion of the mixture of airwith the amount of liquid delivered. This control by the handle Q, ofcourse, has no influence on the amount of air issuing from the nozzle 28for the purpose of atomization of the liquid.

I claim:

1. A spray gun comprising:

(a) a body having a portion adapted to be gripped by the hand;

(b) a container cap carried by said body;

(c) a liquid container removably secured to said cap;

(d) a fluid discharge tube extending through said cap and beingreceivable in said container when the latter is secured to said cap;

(c) said body having an air passage therein for receiving air underpressure;

(f) an air nozzle communicating with said air passage and positionedadjacent to the outlet end of said fluid discharge tube for spraying anyliquid discharged from said tube;

(g) adjustable air conveying means communicating with said air passageand with the top interior of said liquid container for delivering airunder pressure into the container top for forcing liquid from thecontainer and out through said discharge tube, said means beingadjustable for varying the quantity of air entering the container topand thus varying the quantity of liquid discharged from said tube; and

(h) an air exhaust branch communicating with said air passage and havingan outlet opening into the atmosphere so that when said exhaust branchis open. all of the air flowing through said air passage will escape tothe atmosphere and no liquid will be discharged from said tube, saidoutlet opening being closed by the operators finger for preventing anyescape of air to the atmosphere;

(i) whereby liquid will be sprayed that is discharged from said tube.

2. The combination as set forth in claim 1: and in which (a) anadjustable sleeve valve is associated with said air exhaust branch andbeing openable to a desired extent for bleeding off a desired quantityof air to the atmosphere for reducing the amount of air delivered tosaid air nozzle and said air conveying means for altering the quantityof liquid discharged from said tube and thereby altering the amount ofliquid spray delivered by the gun.

3. The combination as set forth in claim 1: and in which (a) said sleevevalve is calibrated for indicating the degree of angular rotation ofsaid sleeve valve and the size of the opening to the atmosphere, thesleeve valve calibrations being associated with a marking on said bodyso as to move past said marking as said sleeve valve is rotated.

4. The combination as set forth in claim 1: and in which said adjustableair conveying means includes;

(a) a second air nozzle communicating with said air passage;

(b) an air inlet pipe for said container and being rotatably carried bysaid cap, the inlet end of said pipe being cut at an angle with respectto the axis of said pipe; and

(c) a handle for rotating said pipe about its axis and being swingableform a position where the inclined inlet end faces said second airnozzle for substantially conveying all of the air issuing from saidsecond nozzle into said pipe and into the top of said container forforcing liquid from said discharge tube, into a position where theinclined inlet end faces away from said second air nozzle and no airissuing from said second air nozzle will enter said pipe and no liquidwill be forced from said discharge tube.

5. The combination as set forth in claim 4: and in which (a) said handleis provided with a pointer and said body is provided with an arcuate rowof spaced apart 7 8 markings over which said pointer travels when saidReferences Cited by the Examiner handle rotates said air pipeabout itsaxis; 7 UNITED. STATES PATENTS (b) wherebys'aid air pipe can beangularly adjusted 2,243,435 5/1941 Mott et a1. at different times toposition the inclined end of said 2,567,099 9/1951 Buss 47 X air pipetoface toward said second air nozzle or at 5 3 191 9 19 5 Gilmomg X adesired angle with respect thereto up to a point where said inclined endfaces away from said second ROBERT REEVES Pnmary Exammer air nozzle. S.H. TOLLBERG, Assistant Examiner.

1. A SPRAY GUN COMPRISING: (A) A BODY HAVING A PORTION ADAPTED TO BEGRIPPED BY THE HAND; (B) A CONTAINER CAP CARRIED BY SAID BODY; (C) ALIQUID CONTAINER REMOVABLY SECURED TO SAID CAP; (D) A FLUID DISCHARGETUBE EXTENDING THROUGH SAID CAP AND BEING RECEIVABLE IN SAID CONTAINERWHEN THE LATTER IS SECURED TO SAID CAP; (E) SAID BODY HAVING AN AIRPASSAGE THEREIN FOR RECEIVING AIR UNDER PRESSURE; (F) AN AIR NOZZLECOMMUNICATING WITH SAID AIR PASSAGE AND POSITIONED ADJACENT TO THEOUTLET END OF SAID FLUID DISCHARGE TUBE FOR SPRAYING ANY LIQUIDDISCHARGED FROM SAID TUBE; (G) ADJUSTABLE AIR CONVEYING MEANSCOMMUNICATING WITH SAID AIR PASSAGE AND WITH THE TOP INTERIOR OF SAIDLIQUID CONTAINER FOR DELIVERING AIR UNDER PRESSURE INTO THE CONTAINERTOP FOR FORCING LIQUID FROM THE CONTAINER AND OUT THROUGH SAID DISCHARGETUBE, SAID MEANS BEING ADJUSTABLE FOR VARYING THE QUANTITY OF AIRENTERING THE CONTAINER TOP AND THUS VARYING THE QUANTITY OF LIQUIDDISCHARGED FROM SAID TUBE; AND (H) AN AIR EXHAUST BRANCH COMMUNICATINGWITH SAID AIR PASSAGE AND HAVING AN OUTLET OPENING INTO THE ATMOSPHERESO THAT WHEN SAID EXHAUST BRANCH IS OPEN, ALL OF THE AIR FLOWING THROUGHSAID AIR PASSAGE WILL ESCAPE TO THE ATMOSPHERE AND NO LIQUID WILL BEDISCHARGED FROM SAID TUBE, SAID OUTLET OPENING BEING CLOSED BY THEOPERATOR''S FINGER FOR PREVENTING ANY ESCAPE OF AIR TO THE ATMOSPHERE;(I) WHEREBY LIQUID WILL BE SPRAYED THAT IS DISCHARGED FROM SAID TUBE.